Mastercard Incorporated (stylized as MasterCard from 1979 to 2016 and mastercard from 2016) is an American multinational financial services corporation headquartered in the Mastercard International Global Headquarters in Purchase, New York, United States. The Global Operations Headquarters is located in O'Fallon, Missouri, United States, a municipality of St. Charles County, Missouri. Throughout the world, its principal business is to process payments between the banks of merchants and the card issuing banks or credit unions of the purchasers who use the "Mastercard" brand debit, credit and prepaid to make purchases. Mastercard Worldwide has been a publicly traded company since 2006. Prior to its initial public offering, Mastercard Worldwide was a cooperative owned by the more than 25,000 financial institutions that issue its branded cards.